West Falmouth Harbor Eelgrass Bed Extent, 2010-2019, generalized

West Falmouth Harbor (West Falmouth, MA, USA) has been experiencing a dramatic increase in nitrogen loading from an upgradient municipal wastewater treatment facility since the early 2000’s. As part of a long-term study into the effects of this nitrogen enrichment, we have been assessing changes in the extent and health of the eelgrass (Zostera marina) community within the harbor. We conducted side scan sonar surveys and analyzed them using SonarWiz and ArcGIS to delineate the extent of continuous seagrass bed within the harbor. The goal of this dataset is to assess changes in eelgrass habitat extent; small bare patches within the larger seagrass bed due to anchor scars and mooring scouring were not digitized. Groundtruthing of the edges was done with a combination of diver surveys, underwater video, and surface surveys at low tide. Surveys were run in every year from 2010 through 2022 and we plan to continue them into future years. Data analysis is ongoing and shapefiles will be added as they are run through quality assessment. Details for the 2010 data collection and analysis are detailed in Hayn 2012: Exchange of nitrogen and phosphorus between a shallow estuary and coastal waters, Appendix 3, permanently archived at https://hdl.handle.net/1813/31380.